Wrangling water: 2019 Spring runoff forecast is in

JACKSON HOLE, WYO — As daytime temperatures rise, snowpack melts out into mountain rills and streams feeding larger creeks and rivers. So it begins anew: springtime in Wyoming.

Buckrail chatted with Brian Stevens, water operations manager for the Bureau of Reclamation. He’s the guy behind the delicate orchestration of water flow in the Upper Snake River Basin encompassing western Wyoming/eastern Idaho. The Bureau is charged with managing water (and hydroelectric power) resources in the west, balancing varied water interests with diversion, delivery, and storage practices.

Despite the notion that late snows (February was ferocious) made for a huge snowpack, Stevens doesn’t see it reflected in his data.

“It’s not quite what we had last year,” Stevens said about the snowpack. Spring 2018 followed one of the more milder Jackson Hole winters. “2017 was big but this is nowhere near that.”

Teacup streamflow, storage. (Bureau of Reclamation)

The 4.3 million-acre feet of snowpack was historic in April 2017 but this year’s snowpack is looking more typical of year’s past. The runoff forecast for May 1 was 107% of normal. The Upper Snake River system is currently at 79% of capacity.

All numbers indicate Stevens is right where he wants to be in anticipation of spring runoff. Reservoirs were drawn down a month or so ago, allowing them to capture peak flows in about 3-4 weeks. All lakes and reservoirs are now on the rise, according to Stevens.

On the Wyoming side of the Snake’s run—Grassy Lake (94%), Jackson Lake (78%), and Palisades (53%). Idaho reservoirs are running near capacity.

Jackson Lake and Palisades Reservoir should be about full near the end of June, Stevens said.

Stevens doesn’t see any major flooding issues in the Upper Snake River Basin this spring. Everything points to a fairly typical spring.

Bureau of Reclamation reps will be in Jackson along with US Army Corps of Engineers to discuss this spring’s runoff, streamflows, flooding potential. (Bureau of Reclamation)

For those that wish to really geek out on water management, the Bureau of Reclamation will host a meeting to present streamflow forecasts and projected reservoir operations for Jackson Lake Dam and other Snake River reservoirs on May 23. The meeting will be held at the 49er Inn conference room, 330 W. Pearl Street in Jackson beginning at 5:30pm.

The meeting will focus primarily on the runoff forecast for the Snake River near Heise, Idaho, water supply outlook, river flow management and snowpack conditions. The US Army Corps of Engineers and Reclamation will be on hand to present and answer any questions.

According to the Corps, there may be potential for some flooding along the Snake River in Teton County due to possible significant inflows from tributaries delivery snowpack melt. These tributaries also may experience high flows and flood flows. Caution is advised in these areas during the snowmelt season.

Buckrail asked Stevens for his guesstimate at a highwater mark on the Snake River above the Palisades Reservoir near Alpine. We did explain that he would likely be declared ineligible to win the Dave Hansen Whitewater High Water Heyday Contest.

“I think peak will be xx,xxx cfs (redacted)…and you can just park that boat in my driveway,” Stevens said.

Think you know what the high water mark will be this year? Make sure to enter the High Water Heyday Contest for your chance to win a 14ft AIRE Tributary raft. And don’t forget to invite Brian Stevens out on a float this summer!


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